Dynamic Analysis Technology For Mechanics Of Snubbing String In Injection Well

Snubbing service is a well bottom technology which lifting or descending string and other operation for enhancing oil recovery.This operation can be done without increasing the wellbore pressure or fluid production.Compared with routine operation,snubbing service has low pollution to reservoir,simple operation process and high operation efficiency.This brand new borehole operation should be spread widely.In this thesis,the topic is the pipe string force analysis for snubbing service in water injection well which has corrosive medium.High pressure and high temperature experiments for well test is based on well operation history.With the data from corrosion experiments,corrosive rate prediction model is built.Modification for the pipe thickness is also included in this model.It took the measured value of well trajectory,the weight of well pipe,the effect of piston force in well bottom,the stability bucking of the well pipe,contact counter force and friction in the string inner wall into consideration.Computing wellhead axial load is taken as purpose.The whole pipe system is taken as research object.With the theory of finite element,pipe is divided into numerous space beam unit.The theory of gap element is used to simulate the contact between pipe string and inner wall of the pipe.The definite solution equation and the analysis model of space mechanical pipe column operated with pressure,and the mechanical analysis software of snubbing string in injection well that contain corrosive medium was established based on above mentioned model and theoretical means.Analyses of influencing factors were made based on the data of well A.The influence of different corrosion rates and different well types on load of wellhead,and the influence of different corrosion condition within pipe strings on the relation curve between buckling force and unsupported length,were analyzed.